Biochemical and biological properties of the venom from Russell's viper (Daboia russelli siamensis) of varying ages.

Russell's viper (Daboia russelli siamensis) venoms of four different lengths (21-25 cm, 40-60 cm, 81-90 cm and 101-110 cm) were studied by SDS-PAGE electrophoresis and immunoblotting. Studies on biological and biochemical properties of the venom were also carried out. The venom of young snakes (21-60 cm) had a high lethal potency and possessed powerful coagulant and defibrinogenating activities compared to adults (101-110 cm). As snakes aged, these activities decreased. Potent capillary permeability increasing activity was detected in venom of 40-60 cm snakes and was the lowest in the youngest snakes (21-25 cm). SDS-PAGE electrophoresis and immunoblot of venoms showed that venom from the youngest snakes has fewer protein bands; the number of bands increased as the snakes aged. Snakes more than 91 cm long demonstrated no striking differences in the protein pattern.

Local compression pads as a first-aid measure for victims of bites by Russell's viper (Daboia russelii siamensis) in Myanmar.

A prospective study of the efficacy of applying local pressure by compression pads in retarding spread of venom was carried out on 15 cases of bite by Russell's viper (Daboia russelii siamensis) in Myanmar. A firm rubber pad was applied with cotton bandaging over the site of bite and the limb was immobilized with a splint. Serial monitoring of venom levels by enzyme immunoassay (EIA) was carried out at 15 min intervals for 1h (2h in one case) while the pad was in place and at 15 and 30 min after its removal. A rise of 10-40ng/mL in serum venom antigen level was observed in most cases after removal of the pad. The central movement of venom antigen was retarded in 13 of the 15 cases. Mild haemostatic changes (factor V and X assays and screening tests) were observed in 10 pad-treated cases measured at the time of onset of incoagulability of blood. The side effects observed while the pads were in place were minimal, consisting of swelling, pain and tenderness, and were well tolerated by most patients (for up to 2h by one patient), except for 2 who had incisions or bruising at the site of the bite.

Humoral response following Russell's viper (Daboia russelli siamensis) bites in Myanmar.

A prospective study of the development, intensity and protective ability of the antibody response to Russell's viper bite and its relation to the severity of envenoming was carried out in 15 patients 3 to 116 weeks after the bites using enzyme immunoassay. Retrospective screening in 123 cases revealed antibody in 112/123 (91%) which could be detected from 1 week to 15 years after the bite. A slow peaking (30 weeks) and waning of antibody response was observed in the majority of cases. Development of antibody response was related to the initial venom level, rather than to the delay between bite and antivenom therapy, or the dose of antivenom. Uraemia depressed the IgM response to venom.

The efficacy of compression immobilization technique in retarding spread of radio-labeled Russell's viper venom in rhesus monkeys and 'mock venom' NaI131 in human volunteers.

The efficacy of the modified compression immobilization technique in retarding spread of radio-labeled Russell's viper venom in 3 rhesus monkeys (Macaca mulata) and "mock venom" NaI131 in 14 human volunteers was studied. 0.1 microgram of Russell's viper venom having 10 microCi radioactivity in 0.2 ml normal saline containing 0.5% bovine serum albumin was injected subcutaneously at the lateral aspect of the right hind limb of a rhesus monkey. A hand-tight bandaging of a rubber pad measuring 55 x 28 x 16 mm over the injection site and splinting effectively retard spread of radio-labeled venom for the entire length of time applied, although complete immobilization was not achieved. In human volunteers, application of a pad measuring 60 x 50 x 17 mm over the subcutaneous injection site of 20 microCi or 12 microCi/0.2 ml NaI131 with a hand-tight bandaging (60 +/- 10 mmHg) and immobilization of limb was found to be effective in retarding the movement of radioactive NaI131. These results suggested that the compression pads tried in this study effectively retard the spread of radio-labeled Russell's viper venom (MW ranging from 20,000-90,000) and radioactive NaI131 (MW 150) from the site of injection. Thus, it is highly likely that the present compression pad will be useful as a first-aid measure in Russell's viper bite victims.

Heparin therapy in Russell's viper bite victims with impending dic (a controlled trial).

A controlled clinical trial of low-dose heparin was carried out in confirmed cases of Russell's viper bite. Twenty-eight patients with coagulable blood and serum FDP levels (more than 80 micrograms/ml) were included in the study. They were randomised to receive low-dose heparin in an initial dose of 50 units/kg body weight intravenously immediately after antivenom followed by a continuous infusion of 10 units/kg/hr in isotonic saline for 24 hours, or antivenom alone. Response to treatment was assessed clinically as well as by serial measurements of coagulation factors and biochemical variables. No features of systemic envenoming developed in any patient after treatment, but one patient in each group developed microscopic haematuria. No systemic bleeding or acute renal failure occurred in any patient. Recovery rate from the clotting defect was similar in the two groups, but in patients with initially very low fibrinogen levels there was a tendency for the heparin to restore fibrinogen faster than in comparable patients who did not receive heparin.